Technological and social development will bring a surge in mobile and wireless traffic, and a decade later, mobile broadband traffic will reach a thousand times more than that of today. In the prior art, it is difficult to meet such a requirement by improving spectrum efficiency, and therefore usage of large bandwidth of a high frequency band has become an inevitable trend. To meet a requirement for rapid growth in mobile data rates in the future, a millimeter-wave band, as a most promising technology, has advantages of a short wavelength and a wide frequency band. However, compared with microwave communications, a millimeter wave is more susceptible to atmospheric absorption, for example, of rain and air, resulting in a problem of a large free-space loss in a transmission path. More studies show that large array antenna and beam alignment technologies are desired to resolve the foregoing problem. To be able to implement the large array antenna and beam alignment technologies, commercial chips may be used for intelligent stacking. Currently, because device errors are inherent in individual chips, it is difficult to determine a phase relationship output by a phase-locked loop. As a result, phase noise output by multiple channels is independent, and overall characteristics of synthesized phase noise have changed, which not only results in a phase offset, but also brings amplitude fluctuation and amplitude varies with time. Local phase noise of each of the multiple modules is independent, resulting that a beam deviates from a specified value and that an irregular shake occurs in spatial beam synthesis, causing interference. Therefore, signal distortion compensation needs to be performed for a received signal. Otherwise, symbol synchronization and equalization may be affected, resulting in an increased bit error rate of a system.
Because all chips have different sources after multiple chips are stacked, current common phase noise immunity algorithms are ineffective for phase noise of different sources. Therefore, to enable gain compensation for multiple channels, a multi-channel digital automatic gain control method and control apparatus is provided in the prior art. When there are two or more than two channel circuits and a gain amplifier corresponding to each of the channel circuits, a digital signal processing (DSP) is used to make each channel output operate according to multiple selectable instructions and parameters stored in the DSP, and a control measure iteration algorithm is used to ensure that output gains of multiple channels are best controlled.
However, by using the solution of the prior art, the output gains of multiple channels have to operate according to the multiple selectable instructions and parameters stored in the DSP. The whole solution requires multiple single-chip microcomputer chips and complex control, which increases costs and difficulty for implementing the solution.